With the continuous development of the 3rd Generation (3G) technologies, the requirements over the Iub interface bandwidths becomes higher and higher. In Asynchronous Transfer Mode Radio Access Network (ATM RAN) mode, E1 transport is generally adopted, but it is expensive and provides limited bandwidths and therefore does not satisfy the requirements for more bandwidths. Fast Ethernet (FE) access, such as Digital Subscribe Line (DSL) access, is adopted in an Internet Protocol (IP) RAN and provides high bandwidths. Compared with E1 transmission, FE access normally does not guarantee effective Quality of Service (QoS) and does not meet the needs of real-time traffic and high-priority traffic. In view of this, the concept of branch transmission emerges. One branch is ATM over E1 for use in an ATM network; one branch is IP over FE for use in an IP network. Traffic that requires high QoS such as voice and real-time traffic is transported over E1; non-real-time traffic that requires low QoS is carried over FE.
The Iub interface includes three channels: Operation & Maintenance (OM) channel, signaling channel and traffic channel. The OM channel is a maintenance channel between a base station (e.g. Node B) and a maintenance node, and is used by the maintenance node to maintain the base station remotely. However, during research and practice of the prior art, the inventor discovers the following problem:
In an ATM RAN and an IP RAN, there is only one OM channel altogether, so that the maintenance node will be unable to maintain the base station remotely when the OM channel fails.